The mechanical piano is usually associated with triple pedal mechanisms. One of the pedal mechanisms is called as a loud pedal mechanism which makes the sound prolonged (or loud) by holding off all the dampers provided for music wires. The loud pedal mechanism is sometimes called "damper pedal mechanism".
The second pedal mechanism is called as a soft pedal mechanism which varies the sound in quality (or in volume) by causing fewer than the normal number of strings to be struck or by bringing the hammers nearer the strings. The soft pedal mechanism is sometimes called as "shift pedal mechanism", especially in the case of the grand piano.
The third pedal mechanism is known as a sostenuto pedal mechanism, and the sostenuto pedal mechanism is used for prolonging the sound by holding off the associated damper independently from the others. When the player depresses a key, the key action mechanism associated with the depressed key causes the damper to leave from the music wire, and, then, the hammer strikes the music wire to produce a sound assigned to the depressed key. If the player operates the sostenuto pedal by the foot and, then, releases the key, the damper keeps off to prolong the sound for a while. The sostenuto pedal mechanism thus arranged is convenient for the variety of a musical expression. Namely, whenever the player needs to depress another key by the same finger without any rapid attenuation of the previous sound, the player operates the sostenuto pedal for prolonging the sound and moves his finger onto another key for depression.
In a typical mechanical piano, the triple pedals are provided under the keyboard so as to be operated by the feet of the player, and the sostenuto pedal is located between the other two pedals. The present invention appertains to the sostenuto pedal mechanism, and, for this reason, description is hereinbelow made for the prior art sostenuto pedal mechanism for better understanding of the Applicant's invention.
An essential part of the prior art mechanical piano is illustrated in FIG. 1 and largely comprises a key 1 provided on a key bed 3 and linked with a key action mechanism (not shown), a damper mechanism 5 engageable with the rear end portion of the key 1 and coupled to a damper 7, and a sostenuto mechanism 9 coupled to the damper mechanism 5. The damper mechanism 5 has a damper lever 11 connected at one end thereof to a damper lever flange 13 which in turn connected to a damper lever rail (not shown). The other end portion of the damper lever 11 is slightly spaced apart from the rear end portion of the key 1 under the releasing of the key 1, however, brought into engagement therewith upon a depression of the key 1. The damper mechanism 5 further has a damper block 17 angularly rotatable around a pin member 19, and a damper lever 21 interconnecting the damper block 17 and the damper 7. The damper 7 is usually in contact with a music wire 23 for restriction on a free vibration produced in the music wire 23, however, momentarily leaves from the music wire 23 upon the depression of the key 1.
The damper block 17 is provided with a tab lip 25 turnable with respect to the damper block 17, and the tab lip 25 is forced by a spring 27 in the counter-clockwise direction. With the resilient force, the tab lip 25 usually comes into abutting engagement with a tab flange felt 29. The tab lip 25 has a projection 31 covered with a tab lip cloth 33 and confronts to a blade member 35 attached to a sostenuto rod 37. The sostenuto rod 37 is rotatable around the center axis thereof and engaged with a sostenuto pedal 39 through a pedal rod 41. When the sostenuto pedal 39 is depressed by the player, the sostenuto rod 37 is driven for rotation in the clockwise direction over a certain angle, and, accordingly, the blade member 35 is brought into abutting engagement with the projection 31, thereby lifting the damper block 17 and, accordingly, the damper 7 to leave from the music wire 23. The blade member 35, the sostenuto rod 37, the pedal rod and the sostenuto pedal 39 as a whole constitute an essential part of the sostenuto mechanism 9. The blade member 35 and, accordingly, the sostenuto rod 37 are shared by all of the keys associated with the damper mechanisms, and provided on the front or the player's side with respect to the damper mechanisms.
When the player depresses the key 1 without any operation on the sostenuto pedal 39, the rear end portion of the key 1 is brought into abutting engagement with the damper lever 11 and causes the damper lever 11 to rotate in the counter-clockwise direction with respect to the damper lever flange 13. With the lifting motion, the damper 7 leaves from the music wire 23, and the music wire 23 produces a sound due to a striking motion of a hammer driven by the key action mechanism. However, if the key 1 is released, the damper mechanism 5 is allowed to pull down the damper 7 toward the music wire 23, so that any free vibration is restricted by the damper 7.
If, on the other hand, the sostenuto pedal 39 is depressed by the player's foot in the depression of the key 1, the sostenuto rod 37 is driven for rotation in the clockwise direction, and the blade member 35 causes the tab lip 25 to rotate in the counter-clockwise direction, so that the damper block 17 and, accordingly, the damper rod 21 are lifted up so as to allow the damper 7 to leave from the music wire 23. The blade member 35 keeps the position in so far as the sostenuto pedal 39 is depressed, and, for this reason, the damper 7 does not return to the engaging position with the music wire 23 even though the key 1 is released. This results in that the music wire continues to vibrate, thereby prolonging the sound produced.
If the key is depressed after the operation on the sostenuto pedal 39, the tab lip 25 is brought into abutting engagement with the lower surface of the blade member 35, however, no influence takes place in the lifting motion. When the player releases the key 1, the damper lever 11 returns to the original position without any restriction by the sostenuto mechanism 9.
The sostenuto pedal mechanism thus arranged allows the music wire to prolong the sound produced therein and is desirable for the expansion of the musical expression. For example, sustained bass sounds are preferable for a gentle piano music such as the Chopin's cradle song, and such a sustained bass sound is achieved by using the sostenuto pedal mechanism.
However, a problem is encountered in the prior art sostenuto pedal mechanism in operability. In detail, the loud pedal is usually operated by the right foot of the player, however, not only the soft pedal but also the sostenuto pedal are depressed by the left foot of the player. Whenever the player operates wants to sustain an extremely soft sound by using the soft pedal mechanism, his left foot needs to simultaneously depress the sostenuto pedal. This requests the player to turn his left foot over the right angles around the heel. However, this attitude is unnatural for the human being.